Obesity rates are increasing in the US, with no signs of slowing; obesity is increasing in all age groups, races and both sexes. It is higher among women of reproductive age and is growing rapidly among children. In order to curtail this complex, global epidemic, it is critical to identify modifiable environmental risk factors such as food security status; proximity to supermarkets, fast food restaurants and recreational facilities; transportation; neighborhood safety and crime-that contribute to nutrition, health disparities, and obesity risk in these populations. Postpartum women are of particular interest because of changes occurring in weight and growth that are immediately influenced by their environments. The proposed research project will assess neighborhood and socio-environmental influences on nutrition and obesity by collecting a broad range of data on participants' communities an ongoing study of postpartum weight retention. Socio-environmental data will be collected and linked to a vast array of detailed individual-level socio-demographic, dietary and behavioral data existing on this cohort. The project's specific aims are: 1) To develop an enhanced framework for this analysis based on formal ethnographic study of the food environment; 2) Using this model, to assess the effect of environmental factors on dietary intake, food security status, and postpartum weight retention; 3) To assess the generalizability of the postpartum study sample by comparing them to women from a representative sample; and 4) To develop a spatially explicit, neighborhood food environment index related to obesity. This study involves data collection and analysis of compositional (e.g. census), contextual (e.g. food resources), and spatially derived data (e.g. distance to food resource) on health outcomes under the supervision of established investigators. Accomplishing the aims of this proposal will expand current understanding of the food environment and will inform further study of alternative strategies for measurement and analysis of environmental influences on health. The paramount goal of this career award is to furnish the PI with supervised research experience and didactic training in sociology, economics, hierarchical and spatial analysis; these experiences will lead to R01 submission and establishment of the PI as an independent investigator.